what if assad starts targeting turkey with aircraft? >> that changes everything, nic robertson. thank you so much for joining me. thank you so much for watching. i'm sure wolf will be all over this and of course debate night in denver. "the situation room" begins now. >>> brooke, thanks very much. happening now, we're counting down to tonight's presidential debate. mitt romney's motorcade just pulled up at the debate hall. president obama's expected to arrive in denver any minute as well. we'll be talking with top supporters of each candidate. the former new york city mayor rudy giuliani, he'll join us live this hour. also we'll be hearing from both candidates' wives in special cnn interviews. today, by the way, is the obama's 20th wedding anniversary. so what's it like spending the night with the romneys? i'm wolf blitzer, you're in "the situation room." >>> 34 days from the presidential election but much more importantly right now at least right now we've reached what may be the most decisive night of the 2012 campaign, the first presidential debate at the university of denver